Electric fan



FIG. 1 is a front elevation view of an electric fan, showing my new design;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a side elevation view thereof, the opposite side being substantially a mirror image of that shown, excluding the adjusting knob; and

FIG. 4 is a top plan view thereof. 

The ornamental design for an electric fan, as shown and described. 